This study is an observational cohort study of hospitalized patients with fever. This study will collect demographic data, history of illness, signs and symptoms, results of laboratory tests, clinical course, treatment and outcome. This study conducted at eight INA-RESPOND hospitals. Potential study patients will be any patients (both children and adults).

This study is an observational cohort to identify the etiologies of acute febrile illness (less than or equal to 2 weeks), which are thought to be endemic or novel in a certain area. Therefore, there are no hypotheses that require sample size calculation to be tested. It is expected that this study will enroll a minimum of 200 patients per site: approximately 100 adults and 100 pediatric cases. The final sample size is therefore estimated to be 1600.

Primary Objective:

To identify the etiology of acute febrile illness cases and evaluate clinical manifestations and outcomes.

Secondary Objectives:

1. To provide clinical data that are essential for improving and/or developing clinical management and health policies.
2. To enhance research capacity and networking for infectious diseases in Indonesia by improving clinical research site capability in conducting research relevant to public health.
3. To establish a repository of biological specimens for future study, such as determining the etiology of undiagnosed fever and/or its pathogenicity and its public health importance.

This study will be conducted at all the INA-RESPOND hospitals (8 hospitals):

• Dr. Cipto Mangunkusumo Hospital , Jakarta
• Penyakit Infeksi Prof. Dr. Sulianti Saroso Hospital, Jakarta
• Dr. Hasan Sadikin Hospital, Bandung
• Dr. Kariadi Hospital, Semarang
• Dr. Sardjito Hospital, Yogyakarta
• Dr. Soetomo Hospital, Surabaya
• Sanglah Hospital, Bali
• Dr. Wahidin Soedirohusodo Hospital, Makassar

The study will enroll eligible fever patients for a period of up to 1 year. Follow-up may be up until one year after last subject is enrolled. Stored samples will be investigated during the study and/or after study completion.

After enrollment, patients will be seen at 14-28 days and at 3 months post enrollment. Patients will be seen every 3 months (6, 9, and 12 months within a window period of +/- 14 days) until cured and no related symptoms persists or the one year time point is reached. The samples will be collected for storage at enrollment, the 14-28 day visit, at 3 months and every 3 months thereafter if not cured.

Inclusion Criteria:

• Age ≥1 year
• Acute febrile illness requiring hospitalization (fever defined as temperature recorded ≥38.0°C during the first 24 hour period of hospitalization).
• Hospitalized within the past 24 hours.
• Willing to allow storage of blood and other specimens for use in future studies of infectious diseases.

Exclusion Criteria:

• Hospitalized within the past 3 months, not including current hospitalization for acute febrile illness.
• Inpatient transfer from another hospital.
• A known medical disorder or other circumstance, which in the opinion of the PI might make the participation of the individual unsafe or difficult.

Examples include, but not limited to: mental illness which could affect compliance with protocol, an anemic patient preventing blood draw.

Hospitalized patients with acute febrile illness.

No plan to share data

We analyzed all subjects enrolled and excluded 6 participants who were not eligible.

48 hours after study related blood drawn

Any untoward or unfavorable medical occurrence in a human subject that occurs within 48 hours of a study-related blood draw that is possibly, probably, or definitely related to the blood draw. Any event outside of this 48 hour window period will not be considered an AE for this study.